1. Field
Exemplary embodiments of the present invention relate to a semiconductor device and a method for fabricating the same, and more particularly, to a semiconductor device including a contact, such as a bit line contact, and a method for fabricating the same.
2. Description of the Related Art
As semiconductor devices are highly integrated, a variety of methods for forming a semiconductor device pattern within a limited area may be proposed. Although reducing the critical dimension (CD) of patterns is important when implementing a semiconductor device, forming a stable contact between upper and lower patterns is also important. Accordingly, a self-aligned contact (SAC) formation method that forms a contact using an etching selectivity between layers may be implemented to form a stable contact between upper and lower pattern.
FIG. 1 is a plan view illustrating a conventional semiconductor device and a method for fabricating the same, showing the existing SAC formation method.
Referring to FIG. 1, a bit-line-contact conductive material, such as polysilicon, is buried in a bit line contact hole H, and a bit-line conductive layer (not illustrated) is then formed over the bit-line-contact conductive material.
The bit-line conductive layer is selectively etched to form a bit line BL. The CD of the bit line BL may be set to be smaller than the diameter of the bit-line contact hole H because the CD of the line type may be set to be smaller than the diameter of the hole type through a photolithography process.
Since portions of the bit-line-contact conductive material excluding a portion positioned under the bit line BL may cause a SAC fail during a subsequent process, they are removed during a process of forming the bit line BL. However, the bit-line-contact material in a corner having a small exposure area is not completely removed but remains (refer to a symbol A). The remaining portion of the bit-line-contact material may cause an undesirable coupling to a storage node contact or the like, such as an SAC fail, during a subsequent process.